JERUSALEM (AP) — Israel’s powerful foreign minister was charged Thursday with breach of trust but escaped more serious charges in a fraud and money-laundering case that could jeopardize his political career and upend the Israeli political system just a month before parliamentary elections.

The decision by Israel’s attorney general capped an investigation into Foreign Minister Avigdor Lieberman that stretched back more than a decade. Mr. Lieberman, a close ally of Prime Minister Benjamin Netanyahu‘s, immediately came under heavy pressure to resign.

Mr. Netanyahu had no immediate comment, while Mr. Lieberman planned an announcement Thursday evening. In a brief statement, Mr. Lieberman‘s attorneys said they respected the decision and would study it. Mr. Lieberman in the past has denied all accusations and alleged they were politically motivated.

The Soviet-born Mr. Lieberman is head of Yisrael Beitenu, an ultranationalist party that is especially popular with immigrants from the former Soviet Union. With a tough-talking message that has questioned the loyalty of Israel’s Arab minority, criticized the Palestinians and confronted Israel’s foreign critics, he at times has alienated Israel’s allies while becoming an influential voice in Israeli politics.

Yisrael Beitenu and Mr. Netanyahu’s Likud Party recently joined forces and are running together on a joint list in the Jan. 22 parliamentary elections. Opinion polls have predicted the list would be by far the largest bloc in parliament and lead a new coalition government.

While Mr. Lieberman was cleared in the most serious allegations against him, Thursday’s decision nonetheless could force him to step down and throw the joint list into disarray.

It appears that Mr. Netanyahu will be unable to break up the alliance, however, because a deadline for announcing candidates has passed. Mr. Lieberman is Yisrael Beitenu’s main attraction to voters, and his departure would leave Mr. Netanyahu with a list of leftovers with little appeal to the general public.

Thursday’s decision was a reversal for Attorney General Yehuda Weinstein, who last year notified Mr. Lieberman that he intended to indict him on charges that included fraud and money laundering.

Prosecutors long have suspected that Mr. Lieberman illicitly received millions of dollars from businessmen and laundered the cash through straw companies in Eastern Europe while he was a lawmaker and Cabinet minister. In his decision Thursday, Mr. Weinstein said the case was not strong enough.

“I am convinced that there is no reasonable chance of a conviction in the offenses Lieberman is suspected of and that case should be closed,” Mr. Weinstein wrote.

Instead, Mr. Lieberman was charged with the lesser offense of receiving official material from the investigation against him from the former Israeli ambassador to Belarus.

The envoy received the documents from the Foreign Ministry, which sought additional information on Mr. Lieberman from Belarus authorities. The ambassador, Zeev Ben-Aryeh, reached a plea bargain in the case earlier this year.

Israeli law is unclear about whether Mr. Lieberman must resign. There is a legal precedent for politicians to step down when they face charges that compromise public trust in them, but Mr. Lieberman could decide the charges don’t warrant that he resign.

Analysts said Mr. Weinstein, or even the Supreme Court, could become involved if Mr. Lieberman decides to remain in politics.

Moshe Negbi, Israel Radio’s legal affairs commentator, said the pressure to step down will be great.

“What matters is not necessarily the formal severity of the crime but the potential harm in the public’s faith in the government and whether the person can continue to project integrity,” he said. “This is the foreign minister of Israel. … He is the face that represents us, and the actions attributed to him become part of the image of the state of Israel.”

Three opposition leaders — Shelly Yachimovich of Labor, former Foreign Minister Tzipi Livni of the new “Movement” Party and Yair Lapid of the Yesh Atid Party — all called for Mr. Lieberman‘s dismissal.

Court rulings in other, more serious criminal cases against Cabinet officials forced them to resign. Facing the prospect of an indictment, former Prime Minister Ehud Olmert announced his decision to step down in 2008 before formal corruption charges were filed against him. Olmert this year was cleared of most charges but convicted of breach of trust.

The blunt-talking Mr. Lieberman has amassed power with support from immigrants from the Soviet Union and other Israelis drawn to his broadsides against Israeli Arabs and dovish groups, as well as the Palestinians and Western Europe.

Mr. Lieberman, who once worked as a bar bouncer, immigrated to Israel in 1978 from Moldova in the former Soviet Union.

Speaking in a Russian-accented monotone, he became a national figure in 1996 as a top aide to Mr. Netanyahu during his previous term as prime minister. He later quit Mr. Netanyahu’s Likud party and was elected to parliament in 1999 as head of Yisrael Beitenu (Israel Our Home), a secular hawkish party he established to represent the more than 1 million immigrants from the former Soviet Union.

His party has gained strength since then. It was the third largest in 2009 elections, drawing many votes from native Israelis as well as his traditional base.

Mr. Lieberman is known for inflammatory rhetoric that has at times agitated his partners in government. He has called for executing Israeli Arab lawmakers who met with leaders of the Palestinian militant group Hamas. As an opposition lawmaker in 2008, he said Egypt’s then-President Hosni Mubarak “can go to hell.”

More recently, Mr. Lieberman pushed a series of legislative proposals that critics said were anti-Arab, including a failed attempt to require Israelis to sign a loyalty oath or have their citizenship revoked, and calls to redraw Israel’s border to place Arab towns under Palestinian jurisdiction.

He embarrassed Mr. Netanyahu in the past by expressing contrasting views to that of the government, including skepticism over the chances of reaching peace with the Palestinians.

Mr. Lieberman has called Palestinian President Mahmoud Abbas an “obstacle to peace” and urged his removal so that peace talks that collapsed in 2008 could be revived.

Earlier this week, he lashed out at the international community, saying many world leaders would sacrifice Israel to radical Islam just as Europe appeased the Nazis before World War II.